Portable electronic devices, such as cell phones, notebook computers, netbook computers, and the like are typically charged through a charger that includes a port power switch. As the current drawn by the portable device increases, temperature of the port power switch tends to increase. In general, the temperature rise may occur due to internal power dissipated by the power switch and other factors such as environmental temperature rise. This increase in temperature may cause reliability and safety issues within both a portable device as well as the charger.
Known approaches to this temperature rise problem aim to reduce the internal power dissipation by turning off the charger. Generally, these solutions include thermal and/or ambient sensors that monitor the temperature of the port power switch. If the temperature exceeds the operating range, the switch is turned “off” until the charger cools down to a desired temperature. Subsequently, the switch is turned on.
Thus, the known approaches require alternately turning on and off the port power switch for a predefined time to decrease the internal power dissipation. Alternate switching on and off, however, provides a pulsed output. This causes the average power available to be delivered to a portable device to be reduced over time. Moreover, repeated port power switch “on-and-off” cycling is an undesirable effect that may result in reduced portable device lifetime.
Therefore, there remains a need for a suitable method and system that can efficiently regulating a charger temperature without affecting the charger operation.